1. Field of the Invention
This invention relates to apparatus and to a method for roll bending heated glass sheets.
2. Background Art
Glass sheets have previously been bent by a conveyor roll bending station that is located downstream from a heating furnace such as disclosed by U.S. Pat. Nos. 5,368,625 Mizusugi and 5,545,245 Mizusugi. These patents disclose a roll bending station having horizontal rolls and laterally spaced sets of inclined rolls downstream from the furnace with the inclined rolls provided in sets having progressively increasing inclination along the direction of conveyance to form each heated glass sheet during conveyance over the inclined rolls.
As disclosed by French Patent 2221409 of inventor Maurice Nedelec, heated glass sheets have also previously been bent by conveyor rolls that are supported and rotatively driven outside of a furnace heating chamber with ends projecting inwardly into the furnace initially in a horizontal orientation. All of the rolls are subsequently simultaneously tilted to form the heated glass sheet within the heated chamber.
One object of the present invention is to provide improved apparatus for roll bending heated glass sheets.
In carrying out the above object, the apparatus for roll bending heated glass sheets in accordance with the invention includes a roll bending station having a heating chamber that is communicated with the interior of a furnace in which glass sheets are conveyed along a direction of conveyance for heating in preparation for bending. A roll conveyor of the apparatus has horizontal extending conveyor rolls that are rotatively driven and spaced horizontally within the heating chamber of the roll bending station along the direction of conveyance extending laterally with respect thereto to support and convey a heated glass sheet to be bent. The roll bending station has a pair of sets of bending rolls that are spaced laterally with respect to each other along the direction of conveyance. A bending roll support and drive mechanism is located externally of the heating chamber to support and rotatively drive each set of bending rolls which extend into the furnace with the bending rolls of each set at progressively increasing inclinations along the direction of conveyance to engage opposite lateral sides of the conveyed glass sheet within the heating chamber and provide bending thereof along a direction transverse to the direction of conveyance.
The roll support and drive mechanism of the roll bending apparatus includes a frame mounted externally at each lateral side of the furnace and has curved support ribs. The roll support and drive mechanism also includes an elongated connector that extends at an inclination along each lateral side of the furnace and provides connection of the adjacent bending rolls to each other. Clamps secure the bending rolls to the curved support ribs to provide the progressive increasing inclination of the bending rolls along the direction of conveyance.
Each elongated connector of the roll support and drive mechanism has an upstream end including a connection for mounting thereof on the associated frame and has a downstream end including an adjustor for adjusting the elevation thereof with respect to the frame to adjust the inclination of the bending rolls. The connection of the upstream end of each elongated connector is a universal connection that permits the adjustment of the inclination of the roll connector and pivoting thereof about its elongated direction as the inclination of the bending rolls is adjusted.
The construction of each bending roll includes a tubular support having a connection to the associated elongated connector. Antifriction bearings are supported by the tubular connector and support a metallic roll support for rotation. A refractory bending roll member of each bending roll is mounted by the metallic roll support member, preferably by a hole in one end thereof that receives the refractory bending roll member with an adhesive providing securement. Another end of the metallic roll support member includes a drive member for rotatively driving the bending roll.
The construction of the clamps that secure the bending rolls to the curved support ribs of the frame include frustoconical clamp members and a clamp actuator that selectively provides clamping of the frustoconical clamp members to the curved support ribs and unclamping thereof to permit adjustment of the inclination of the bending rolls. More specifically, each bending roll clamp includes a single frustoconical clamp member located on one side of a pair of the curved support ribs and a plurality of frustoconical clamp members located on the opposite side of the pair of curved support ribs from the single frustoconical clamp member. The clamp actuator operates between the single frustoconical clamp member and the plurality of frustoconical clamp members to selectively provide clamping thereof against the pair of curved support ribs and positioning of the bending rolls or unclamping thereof to permit adjustment of the inclination of the bending rolls.
The roll bending apparatus also includes an adjustor that provides lateral adjustment of the frames of the bending roll support and drive mechanism with respect to the furnace to accommodate bending of glass sheets of different sizes.
Another object of the present invention is to provide an improved method for roll bending heated glass sheets.
In carrying out the immediately preceding object, the method for roll bending heated glass sheets in accordance with the invention is performed by conveying a glass sheet within a furnace heating chamber along a direction of conveyance for heating to a bending temperature. The conveyance of the heated glass sheet is continued within the heating chamber on rotatively driven horizontally extending rolls adjacent an exit end of the heating chamber and by supporting a pair of sets of bending rolls externally of the heating chamber at opposite lateral sides thereof with bending rolls of each set projecting into the furnace with progressively increasing inclinations along the direction of conveyance. The sets of bending rolls are rotatively driven to engage opposite lateral sides of the conveyed glass sheet to provide bending thereof along a direction transverse to the direction of conveyance.
In performing the roll bending method, the bending rolls are clamped to curved support ribs to provide the support thereof with progressively increasing inclinations along the direction of conveyance and are unclamped from the curved support ribs to permit adjustment of the inclination.
The sets of bending rolls in performing the roll bending method are also laterally adjusted with respect to the direction of conveyance to accommodate bending of glass sheets of different sizes.